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<a href="uniq__id__holder_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
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<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#include &quot;<a class="code" href="uniq__id__holder_8hpp.html">flow/util/uniq_id_holder.hpp</a>&quot;</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span><span class="preprocessor">#include &lt;limits&gt;</span></div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span> </div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1util.html">flow::util</a></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span>{</div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span> </div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="comment">// Static initializations.</span></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span> </div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span>std::atomic&lt;Unique_id_holder::id_t&gt; <a class="code hl_variable" href="classflow_1_1util_1_1Unique__id__holder.html#ad42e76b8fd63b28a0775167c43edfc58">Unique_id_holder::s_last_id</a>(std::numeric_limits&lt;id_t&gt;::min());</div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span> </div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment">// Implementations.</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span> </div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno"><a class="line" href="classflow_1_1util_1_1Unique__id__holder.html#a90705293787069f52372638d5450ef52">   31</a></span><a class="code hl_function" href="classflow_1_1util_1_1Unique__id__holder.html#a90705293787069f52372638d5450ef52">Unique_id_holder::Unique_id_holder</a>() :</div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span>  <span class="comment">/* Get the next available ID in the universe.  Use large type for id_t to avoid overflow.</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment">   * Use atomic&lt;&gt; to ensure thread safety.  Use pre-increment so that the smallest possible ID is reserved and</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment">   * never assigned to an actual m_id (might come in handy for debugging someday, identifying failure of this</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment">   * feature). */</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span>  m_id(++s_last_id)</div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span>{</div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span>  <span class="comment">// Nothing else.</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span>}</div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span> </div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno"><a class="line" href="classflow_1_1util_1_1Unique__id__holder.html#abb06f3132d6a6d1d0c509cbd50b9f768">   41</a></span><a class="code hl_function" href="classflow_1_1util_1_1Unique__id__holder.html#a90705293787069f52372638d5450ef52">Unique_id_holder::Unique_id_holder</a>(<span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1util_1_1Unique__id__holder.html">Unique_id_holder</a>&amp;) :</div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span>  <a class="code hl_class" href="classflow_1_1util_1_1Unique__id__holder.html">Unique_id_holder</a>() <span class="comment">// This (unusual) behavior is explained in class doc header.  Basically new obj = separate obj.</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span>{</div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span>  <span class="comment">// Nothing else.</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span>}</div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span> </div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno"><a class="line" href="classflow_1_1util_1_1Unique__id__holder.html#abb6bab931f868d2a2e933d94f7540b1c">   47</a></span><span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1util_1_1Unique__id__holder.html">Unique_id_holder</a>&amp; <a class="code hl_function" href="classflow_1_1util_1_1Unique__id__holder.html#abb6bab931f868d2a2e933d94f7540b1c">Unique_id_holder::operator=</a>(<span class="keyword">const</span> <a class="code hl_class" href="classflow_1_1util_1_1Unique__id__holder.html">Unique_id_holder</a>&amp;)<span class="keyword"> const</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span>  <span class="comment">// Intentionally blank.  This (unusual) behavior is explained in class doc header.</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span>  <span class="keywordflow">return</span> *<span class="keyword">this</span>;</div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span>}</div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span> </div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno"><a class="line" href="classflow_1_1util_1_1Unique__id__holder.html#a24742b697933e623df30056aebbebfae">   53</a></span><a class="code hl_typedef" href="classflow_1_1util_1_1Unique__id__holder.html#af9cbe2432658aac398498e0a7e96405f">Unique_id_holder::id_t</a> <a class="code hl_function" href="classflow_1_1util_1_1Unique__id__holder.html#a24742b697933e623df30056aebbebfae">Unique_id_holder::unique_id</a>()<span class="keyword"> const</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span>  <span class="keywordflow">return</span> <a class="code hl_variable" href="classflow_1_1util_1_1Unique__id__holder.html#abfd221f9f9a3498c9f697ede78d99938">m_id</a>;</div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span>}</div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span> </div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno"><a class="line" href="classflow_1_1util_1_1Unique__id__holder.html#a50489177a7731618ca130468c3872748">   58</a></span><a class="code hl_typedef" href="classflow_1_1util_1_1Unique__id__holder.html#af9cbe2432658aac398498e0a7e96405f">Unique_id_holder::id_t</a> <a class="code hl_function" href="classflow_1_1util_1_1Unique__id__holder.html#a50489177a7731618ca130468c3872748">Unique_id_holder::create_unique_id</a>() <span class="comment">// Static.</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span>{</div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span>  <span class="keywordflow">return</span> <a class="code hl_function" href="classflow_1_1util_1_1Unique__id__holder.html#a90705293787069f52372638d5450ef52">Unique_id_holder</a>().unique_id();</div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span>}</div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span> </div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span>} <span class="comment">// namespace flow::util</span></div>
<div class="ttc" id="aclassflow_1_1util_1_1Unique__id__holder_html"><div class="ttname"><a href="classflow_1_1util_1_1Unique__id__holder.html">flow::util::Unique_id_holder</a></div><div class="ttdoc">Each object of this class stores (at construction) and returns (on demand) a numeric ID unique from a...</div><div class="ttdef"><b>Definition:</b> <a href="uniq__id__holder_8hpp_source.html#l00106">uniq_id_holder.hpp:107</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Unique__id__holder_html_a24742b697933e623df30056aebbebfae"><div class="ttname"><a href="classflow_1_1util_1_1Unique__id__holder.html#a24742b697933e623df30056aebbebfae">flow::util::Unique_id_holder::unique_id</a></div><div class="ttdeci">id_t unique_id() const</div><div class="ttdoc">Raw unique ID identifying this object as well as any object of a derived type.</div><div class="ttdef"><b>Definition:</b> <a href="uniq__id__holder_8cpp_source.html#l00053">uniq_id_holder.cpp:53</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Unique__id__holder_html_a50489177a7731618ca130468c3872748"><div class="ttname"><a href="classflow_1_1util_1_1Unique__id__holder.html#a50489177a7731618ca130468c3872748">flow::util::Unique_id_holder::create_unique_id</a></div><div class="ttdeci">static id_t create_unique_id()</div><div class="ttdoc">Short-hand for Unique_id_holder().unique_id(); useful when all you want is the unique integer itself.</div><div class="ttdef"><b>Definition:</b> <a href="uniq__id__holder_8cpp_source.html#l00058">uniq_id_holder.cpp:58</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Unique__id__holder_html_a90705293787069f52372638d5450ef52"><div class="ttname"><a href="classflow_1_1util_1_1Unique__id__holder.html#a90705293787069f52372638d5450ef52">flow::util::Unique_id_holder::Unique_id_holder</a></div><div class="ttdeci">Unique_id_holder()</div><div class="ttdoc">Thread-safely construct an ID whose value is different from any other object of this class,...</div><div class="ttdef"><b>Definition:</b> <a href="uniq__id__holder_8cpp_source.html#l00031">uniq_id_holder.cpp:31</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Unique__id__holder_html_abb6bab931f868d2a2e933d94f7540b1c"><div class="ttname"><a href="classflow_1_1util_1_1Unique__id__holder.html#abb6bab931f868d2a2e933d94f7540b1c">flow::util::Unique_id_holder::operator=</a></div><div class="ttdeci">const Unique_id_holder &amp; operator=(const Unique_id_holder &amp;) const</div><div class="ttdoc">This assignment operator is a const no-op.</div><div class="ttdef"><b>Definition:</b> <a href="uniq__id__holder_8cpp_source.html#l00047">uniq_id_holder.cpp:47</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Unique__id__holder_html_abfd221f9f9a3498c9f697ede78d99938"><div class="ttname"><a href="classflow_1_1util_1_1Unique__id__holder.html#abfd221f9f9a3498c9f697ede78d99938">flow::util::Unique_id_holder::m_id</a></div><div class="ttdeci">const id_t m_id</div><div class="ttdoc">The ID. Note its constness alone forbids a classic assignment operator.</div><div class="ttdef"><b>Definition:</b> <a href="uniq__id__holder_8hpp_source.html#l00154">uniq_id_holder.hpp:154</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Unique__id__holder_html_ad42e76b8fd63b28a0775167c43edfc58"><div class="ttname"><a href="classflow_1_1util_1_1Unique__id__holder.html#ad42e76b8fd63b28a0775167c43edfc58">flow::util::Unique_id_holder::s_last_id</a></div><div class="ttdeci">static std::atomic&lt; id_t &gt; s_last_id</div><div class="ttdoc">m_id value of the Unique_id_holder object last constructed.</div><div class="ttdef"><b>Definition:</b> <a href="uniq__id__holder_8hpp_source.html#l00172">uniq_id_holder.hpp:172</a></div></div>
<div class="ttc" id="aclassflow_1_1util_1_1Unique__id__holder_html_af9cbe2432658aac398498e0a7e96405f"><div class="ttname"><a href="classflow_1_1util_1_1Unique__id__holder.html#af9cbe2432658aac398498e0a7e96405f">flow::util::Unique_id_holder::id_t</a></div><div class="ttdeci">uint64_t id_t</div><div class="ttdoc">Raw integer type to uniquely identify a thing. 64-bit width should make overflow extremely hard to re...</div><div class="ttdef"><b>Definition:</b> <a href="uniq__id__holder_8hpp_source.html#l00112">uniq_id_holder.hpp:112</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html"><div class="ttname"><a href="namespaceflow_1_1util.html">flow::util</a></div><div class="ttdoc">Flow module containing miscellaneous general-use facilities that don't fit into any other Flow module...</div><div class="ttdef"><b>Definition:</b> <a href="basic__blob_8hpp_source.html#l00028">basic_blob.hpp:29</a></div></div>
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